228 
island Egholm in Storebelt where it was found in abundance in a 
little pool. In Jutland is was taken on the northern sbore of 
the Scaw where it occurs in a ditch among the dunes near the sea; 
at „Kandestederne u in a bog, and finally in the little pond at 
Lønne near Nørre-Nebel. The male was obsorved only once, namelv 
in Ordrup Mose, Aug. 1909. 
Mononclius dolichurus n. sp. 
PI. II. figs. 6, 10, 11. 
This exceedingly nice and characteristic form was found in 
the wide boggy regions between Hulsig and Kandestederne in Jut¬ 
land. In spite of an eager search in the material it has been 
impossible for me to find more than one specimen, a female. 
Though not still mature — the female organs are just laid down 
and form a little sausage-shaped body which indicates the place of 
the vulva not yet developed — the animal has a length of ca. 4 mm. 
Thus it will probably prove to be larger than most of the other 
species of this genus. 
The front part which tapers very little is beset with two circles 
of rather conspicuous papillæ; behind these the body is incon- 
spicuously constricted as in M. spectabilis. The cavity of the 
mouth, which in optical section appears to be regularly barrel- 
shaped, is probably prismatic and in transverse section triangular. 
The dorsal tooth, which is relativelv small and has its apex turned 
downwards, is placed in the proximal half of the mouth-cavity; its 
distance from the bottom is about the third of the length of the 
former. Besides this tooth some inconspicuous conical prominences 
are found partly opposite to the tooth, partly in the bottom of the 
mouth-cavity. I count all in all seven. Oesophagus has the form 
usually found in the Mononchs but has three or four inconspic- 
uously developed lobes at its proximal end, a case not found in 
other species of this genus (Fig. 11). The tail, after which I have 
named the animal, is longer than in any species of this genus 
hitherto known; it measures but 4 1 h in the length of the animal. 
